Link to the Specification
Seeing as it’s non-obvious to those finding the CG, I thought it would be valuable to point out where to find the “Sourcing In-band Media Resource Tracks from Media Containers into HTML” can be found:
Media Resource In-band Tracks Community Group
This group will develop a specification defining how user agents should expose in-band tracks as HTML5 media element video, audio and text tracks so that Web applications can access the in-band track information, through the media element, in a interoperable manner across user agent implementations.
Media formats of interest are MPEG-2 transport stream, WebM and MPEG-4 file format. Other media formats containing in-band tracks may be considered.
w3c/HTMLSourcingInbandTracks
Note: Community Groups are proposed and run by the community. Although W3C hosts these conversations, the groups do not necessarily represent the views of the W3C Membership or staff.